Re: why anti-AAT arguments are wrong

On May 12, 3:51 am, Marc Verhaegen <m_verhae...@xxxxxxxxx> wrote:
AAT is perhaps not so obvious as many AATers think: humans are terrestrial,
IOW, all human features are adapted to what we are now (after all we live),
so anti-AATers argue that it's unnecessary to explain our features through a
hypothetical (semi)aquatic phase.

Moreover, many/some of them think:
1) apes+monkeys are arboreal + quadrupedal + furred,
2) humans are terrestrial + bipedal + furless,
therefore ITO terrestriality explains bipedality & furlessness.

This is a common logical error type, known as "post hoc ergo propter hoc"
(they think "after" means "because" (English "since" in 2 meanings)), but we
are not bipedal *because* we left the trees (eg, savanna baboons are not
bipedal = what Renato Bender calls "the baboon paradox": baboons are less
quadrupedal than forest relatives etc.).

(BTW, this type of error is also made by a lot of AATers, who think our
bipedality has to be explained by our semi-aquatic past, eg, Algis Kuliukas
thinks our bipedality has to be explained by a wading past, in the same way
as anti-AATers used to think that our bipedality has to be explained by
"coming from the trees to the ground".)

The objection ("a semi-aquatic interludium is unnecessary & unparsimonious")
can best be contradicted "ex absurdo" & "a fortiori":
If their reasoning had been correct, there had also been no need for, eg,
aquatic ancestors of all mammals once (fish-like ancestors say 500 Ma).
But the fact that mammals (& all other tetrapods) have rudiments of
aquaticness such as embryological "gills" etc. leaves (in combination with
other facts) no doubt that our ancestors 500 Ma or so were aquatic.

In the same way (but at a totally different time scale) the fact that we
have a lot of SC fat, reduced olfaction, head+spine+legs in 1 line etc.
leaves IMO no doubt our ancestors spent a lot of time in the water once.

Since these "littoral" features are not (or to a lesser degree) seen in our
nearest relatives the chimps, this semi-aquatic phase must have happened
after Homo & Pan split (probably less than 5 Ma, and in view of the fact
that features can disappear "fast" evolutionarily, probably until much more
recently than 5 Ma, I guess they only started much after the H/P split,
during the Ice Ages, and lasted possibly even until only 200 ka or so).
(Elaine Morgan thinks the H/P split caused or was caused by our becoming
(semi)aquatic, but I see no evidence of this: all that is needed is that our
semi-aquatic (eg, slow-diving) adatations happened not earlier than the H/P
split.)

Anti-AATers say: the features you mention are not littoral at all:
many marine mammals are furred, many non-aquatic mammals are naked, many
non-aquatic mammals are fat etc.
Then I can say: the combination of furlessness + a lot of SC fat is only
seen in mammals that spend a lot of time in water (note the reverse is not
correct), no reason why humans should be an exception.
Then they answer: your statement is incorrect, eg, see the human example
itself: humans (furless & fat) are terrestrial.
Then I say: we are "furless" in the water (no clothes), but "furred" outside
(but this requires that our clothes +-function like the mammalian fur).

The combination in humans of so many features that are in different
combinations seen in water(side) mammals leaves no doubt that our ancestors
until not so long ago were semi-aquatic.
(One of the problems here is: how fast do features disappear?)
Anti-AATers often don't understand that these correlations don't have to be
absolute, but are statistical: one feature alone (eg, no fur) doesn't say
much, but the more features we have that are *often* seen in water(side)
mammals, the less likely our ancestors never were waterside.
The human combination of waterside features is, of course, not seen in any
other waterside mammals (eg, sea otters are lean & furred - IMO due to their
smaller size), but are seen in different combinaitons in (semi)aquatic
mammals.

None of these features is absolute: we're not 100 % naked, we "only" have
about 20 % of SC fat tissues, we're not competely streamlined etc.
These objections are easily answered by our having been only partly aquatic
& by the time that has passed since this semi-aquatic phase.

Another "problem" (no real problem IMO) which anti-AATers think is relevant:
most fossils of "hominids" are found in "savanna-like" milieus or at least
not in the sea.
But here they make a lot of mistakes:
- they confuse fossils with ancestors,
- many of them think australopiths were our ancestors,
- they "forget" that all finds of Homo were clearly next to large bodies of
water (eg, work of Stephen Munro),
- they forget that you can have littoral ancestors & yet live inland (eg, by
trekking inland along rivers etc.),
- some of them even think that when you find ostrich shells next to some
hominid remains, the savanna idea is proven,
- the more fanatic anti-AATers even claim that there was no water at early
hominid finds such as Gona 2.6 Ma (not to mention that some of them even
believe that the butchered animals were exhausted & killed by our ancestors
running after them, only because some people today sometimes hunt like
that!!).

In fact, all known facts are compatible with, eg, this scenario (I'm not
saying it's true, only that it's possible):
Human ancestors after the H/P split began living along the Indian Ocean
shores (where their lifestyle included partime diving for shellfish), and
from the coasts, different side-branches at different times & in parallel
entered the inland along the rivers (leaving archeol.remains etc.).
(This would explain:
- the absence of "African" retroviral elements in our DNA,
-the early finds of Homo in a marine delta (Mojokerto),
- the existence of
island relatives (H.floresiensis, with the typically reduced body &
esp.brain size of island forms),
- the fact that early carcass butcherers used also sea shells to butcher
(google "Choi & Driwantoro"),
- the Paleolithic butcherings not only of riverside bovids etc., but also of
stranded whales, etc.etc.)

Another "problem" that some fanatic anti-AATers make is that we can't have
been waterside since there exist crocodiles or sharks etc.
This is too ridiculous to deserve an answer:
- Lucy was found amid crocodiles eggs, IOW, s/he lived not far from
crocodiles, but it didn't keep Lucy from having lived, so why could that not
have been true for our ancestors? (who were IMO not closely related to Lucy
BTW).
- What about lions etc.in savannas?

Arguments saying that we were not "aquatic" & that therefore AAT (*aquatic*
ape theory) is wrong are totally irrelevant: nobody ever claimed our
ancestors were once fully aquatic.

Conclusion: nothing contradict that human ancestors were littoral once & got
part of their food through slow diving for hard-shelled invertebrates.

______

http://groups.yahoo.com/group/AAT
Description:
* Human evolution based on comparative anatomy & physiology.
* Comparative & fossil information on human & ape evolution.
* Waterside diaspora of Homo after Homo & Pan split ~5 Ma.

AAT:
* Aquatic Ape Theory of human evolution (original term E.Morgan 1982)
* Aquarboreal Apes Theory of Mio-Pliocene apes (aqua=water, arbor=tree)
* Amphibious Ancestors Theory of Plio-Pleistocene Homo (AAT strict sense)

AAT s.s. is based on the behavior/anatomy/physiology/DNA of living humans
compared to chimps & other living animals.

Collection of waterside foods (eg, fruits, (coco)nuts, turtle & bird eggs,
shell/crayfish, water(side)plants, drowned herbivores, stranded whales etc..)
explains unique Homo traits (not seen in apes & australopiths) better than
dwelling in forests or dry plains: huge brain, slow-diving skills, voluntary
breath control, varied vocality, small mouth+chewing muscles, tongue bone
descent, longer airway, projecting nose, poor sense of smell, extreme
handiness & tool use, late puberty, long legs, alined body, poor climbing,
flat feet, fur loss, fatness, profuse sweating, high needs of water, sodium,
iodine, poly-unsat.fatty acids (DHA), etc.
All these features are typically seen in different combinations in waterside
& (semi)aquatic animals, but are strikingly absent in savanna dwelling
mammals.

Homo & Pan separated ~6­4 Ma. Homo populations dispersed along
lakes/shores/rivers in savannas & elsewhere, eg, crossed 18 km sea to reach
Flores 0.8 Ma.
Homo tools/fossils 2.5­0.1 Ma are found near Rift valley lakes & even (sea
level fluctuations hindered fossilisation) Indian Ocean & African coasts,
often amid seashells (Mojokerto, Dungo V Baia Farta, Terra Amata, Table Bay,
Eritrea etc.).

http://allserv.rug.ac.be/~mvaneech/Symposium.htmlhttp://users.ugent.be/~mvaneech/outthere.htmhttp://users.ugent.be/~mvaneech/Fil/Verhaegen_Human_Evolution.htmlhttp://users.ugent.be/%7Emvaneech/Verhaegen%20et%20al.%202007.%20Econ...
of%20Homo.pdf
or google "aquarboreal", "open plain or waterside" etc.

Strange.

Marc,

Humans are communal, communicative, communally territorialistic. If
you can't explain ecological situational factors by which variants
(and groups of variants) of an ape population that have these traits/
behaviors/abilities more than other variants of the population would
be better able to survive and procreate than these other variants then
you don't have a hypothesis.

You don't have a hypothesis.
.

Relevant Pages

  • why anti-AAT arguments are wrong
    ... IOW, all human features are adapted to what we are now, ... aquatic ancestors of all mammals once. ... after Homo & Pan split (probably less than 5 Ma, and in view of the fact ...
    (sci.anthropology.paleo)
  • Re: water needed everywhere
    ... all human features are adapted ... aquatic ancestors of all mammals once. ... after Homo & Pan split (probably less than 5 Ma, and in view of the fact ...
    (sci.anthropology.paleo)
  • Re: Endurance running facts (Re: Evolution = gradual
    ... AAT is perhaps not so obvious as many AATers think: humans are terrestrial, ... IOW, all human features are adapted to what we are now, ... aquatic ancestors of all mammals once. ...
    (sci.anthropology.paleo)
  • Re: What is the Aquatic theory?
    ... terrible claims you make against Elaine Morgan ... >> other mammals and just which mammals those are, ... you look at the features they say we share with these "more aquatic ... why are you still using as evidence features found only ...
    (sci.anthropology.paleo)
  • reconstructing evol.histories : the comparative & analytical method
    ... Trying to reconstruct how our ancestors lived is a historical science - ... extinct & 2) extant animals. ... All our features have gone through selection, IOW, they're functional. ...
    (sci.anthropology.paleo)